The
Harappan Civilisation, "the vastest political experiment before
the advent of the Roman Empire" (Mortimer Wheeler), suddenly came
to an abrupt end around 1700 B.C. All the reasons for its
demise are not yet known, but it was probably directly related
to the Aryans, invading tribes-men from the Russian and Central
Asian steppes. The newcomers called them-sleves Aryas, a
term meaning "superior" and surviving in Iran and Eire/ Ireland.
There are references to the battles of the Aryans with the Dasas
in the Vedic hymns, to the occupation of the Dasas1 land, to the
capture of their possessions, and to the destruction of their
cities. The Indo-Aryan war-god Indra is known as puramdara,
"the destroyer of cities." Agni, the fire-god, is also prominently
mentioned in this capacity, understandably, since many of the
Indus cities were destroyed by fire. The conclusion seems
to be inescapable: the destruction of the Indus cities of
the Dravidians and/or Mundas was the work of the Aryans.

While
the superiority of the Dravidians lay in their urban civilization,
the superiority of the Aryans lay in their military strength.
The invaders relied more on wood for their homes than on stone
and preferred villages to cities at least till the end of the
Vedic period.

The
invading Aryans were divided into a large number of independent
tribes often fighting each other when they were not fighting the
Dasas (Dravidians and Mundas), their common enemy.
The Aryans were highly conscious of their ethnic unity, based
on a common language (Sanskrit is the literary expression of it),
a common religion (Brahminism is its classical form), and a common
culture (love of war and adventure is an integral part of it).
the white Aryans were well aware of the contrast between themselves
and the colored natives who either became Sudras or servants and
dependents of the conquerors or withdrew to the forests and mountains
and to regions beyond the Aryavarta (land of the Aryans) across
the Vindhya Mountains to the South. That the Aryans were able
to maintain their identity implies that they came in large numbers,
in waves of migration, lasting a long period. The Aryans
expanded from the Indus Valley and Punjab eastwards to modern
Uttar Pradesh down the Ganga Valley. The main group of migrants
followed the foothills of the Himalayas, driving the Mundas to
the hills and the Dravidians south to Deccan. All this time
they were still living among the conquered Mundas called Nishadas
or forest tribes.

The
next stage in the Aryan occupation of India falls within 800-550
B.C. At this time Aryavarta had for its boundaries the seas in
the east and the west and the Himalayas in the north and the Vindhya
in the south. The advance to Bengal and Orissa and Gujarat
and Maharashtra and the Dravidian lands of the south took place
not behind battle standards but under the banner of civilizing
missions. The Brahmins, the Aryan missionaries, spread the
Brahminic religion, Vedic culture, and the Sanskrit language;
the Brahmins also increased their status or strengthened their
organization. Alone or in small numbers and away from home,
the wandering Aryans mixed with the Dravidians and Mundas, and
their hybrid descendants moved farther to Dravidian South.
It was at this time that the Pre-Aryans considerably influenced
the Aryans and that the transition from Vedic religion to later
Hinduism had its beginnings. Throughout, the Tamils .of
the extreme South remained independent and standoffish.

The
penetration of the South and Kerala by the Aryans began only during
the Buddhist and Jainist times. It was a slow, gradual process
which was accomplished in a gentle, subtle manner by the missionaries.
It was a conquest, all right; but it was accomplished by the arts
of peace and not by the force of arms. Though the Buddhists
came at the wake of Emperor Ashoka's evangelizing missions, most
of the Vedic Brahmins came only in the seventh and eighth centuries
by way of the West Coast from Tulu Nadu.